Casing centralizer



Jan. 8, 1963 A. N. LovE CASING CENTRALIZER Filed Nov. 28, 1960 IN VEN TOR.

Add/J0@ Z o Ve United States Patent Office 3,072,196 Patented Jan. 8, 1963 3,072,196 CASIN G CENTRALIZER Addison N. Love, Weatherford, Tex., asslgnor to Weatherford Oil Tool Company, Inc., Houston, Tex., a corporation of Texas Filed Nov. 2s, 196s, ser. No. 71352 7 claims. (ci. 16s- 241) This invention relates to centralizers, particularly those of the type utilized in positioning casing and other pipe in oil wells, as preparatory to or in aid of other operations.

Since such centralizers must be designed to iit pipes of dilferent sizes, it is necessary for the industry to prepare and stock complete devices of a variety of different sizes. Moreover, the connecting bars, usually, have been formed of strip spring stock suitably secured to the end collars, as by welding or wedging, or round rod stock either Welded to the collars or lodged therein by separate attaching means.

Consequently, it is an object of the present invention to provide a centralizer in which the end collars are connected by bars of relatively inexpensive round stock which are anchored to the collars by their own resilience so as to form a firm assembly.

A more detailed object is to provide a centralizer in which the spaced collars are connected by outwardlybowed, relatively inexpensive round rod or bar stock which is disposed helically relative to the collars and which are rmly lodged in position by offset ends of the connecting rods which are torsionally twisted in the assembly so that the resilience of the rods rmly maintains the assembly.

Still another object is to provide a novel method of assembling a centralizer of the above type.

These objects are accomplished in my novel centralizer which consists essentially of axially-aligned, spaced end collars each having an annular fold with circumferentially spaced apertures or recesses into which the bent-over or oifset ends of the helical connecting rods are placed. To effect the assembly, one of the rod ends is placed in a hole or recess in one of the collars, then the other offset end of the rod is twisted to facilitate directing the other end into a recess in the other collar so that when the other end is released, the resilience of the rod maintains the assembly.

In the accompanying drawings which illustrate the invention,

FIG. 1 is an elevation of the novel centralizer applied to a casing within a well bore;

FIG. 2 is a view of one of the bowed connecting rods disassembled;

FIG. 3 is a view of the rod in FIG. 2, but taken at 90 thereto;

FlG. 4 is a partial, vertical longitudinal section through the upper collar, a portion being broken away to illustrate the underlying structure; and

FIG. 5 is a schematic, partial horizontal section taken approximately on the broken section line 5-5 of FIG. 1 and also illustrating a step in the assembly process.

FIG. 1 illustrates a section of a casing 8 inserted in a well bore 9 and having applied thereto a stop collar 10 of any suitable design. Mounted on the casing at opposite sides of the stop collar are collars 11 and 12 of the centralizer connected by outwardly-bowed, resilient wire rods, generally designated 13. The collars have annular folds 14 and 17 provided with annularly spaced, opposing apertures or recesses 15 and intervening cutouts 16. Collar 12 is identical with collar 11, except that it is reversed, that is, with its fold 17 near the lower end of the device.

Each of the connecting wire rods 13 has a bowed intermediate portion and angular end portions 18 and 19 which are olfset relative to the axis of the rod in noncoextensive and non-parallel planes. As viewed in FIG. 5, the initial positions of the rod end portions are illustrated at 18a and 1811 in dashed lines, these end portions are torsionally twisted to lie along the inner walls of collar grooves formed by folds 14 and 17.

A liner sleeve 20 is secured, conveniently, by spot welding to the inner wall of each collar in position to overlie its fold 14 or 17. These sleeves are provided, principally for protective and esthetic reasons, the connecting bars being rrnly lodged in position by their own resilience, as explained hereafter. The sleeves are secured in position before the connecting rods are positioned.

In order to assemble the centralizer, one end of each outwardly bowed, resilient connecting bar, bent and olfset as in FIGS. 2 and 3, is inserted in one of the holes or recesses 15 in one of the collars. Conveniently, the bottom offset end 19 of a rod may be initially inserted in a hole or recess 15 of the upper wall of fold 17 in bottom collar 12. The rod is then positioned generally helically with respect to the collars and with the opposite offset end 18a located somewhat outwardly of one of the recesses in the fold 14 of upper collar 11, as represented at 21 in FIGS. 1 and 5. A tool 22 is then applied over the free offset end 18, this tool, conveniently, being somewhat like an open end wrench with a handle portion 22a and an axial slot 22h opening through the opposite end. With the offset end 18a received in tool slot 22h, the tool is then rotated counterclockwise so as to bring the end 18a into general alignment with the immediately adjacent portion of fold 1.4 in collar 11 and so that end portion 13 will be insertable in the adjacent hole or recess 15 in the under surface of fold 14. When the bar is swung about its lower end and its upper end 18 is inserted and driven as far as possible through the mentioned recess 15 and along the inner face of fold 14, and tool 22 removed, both ends 18 and 19 of the rod will be twisted, as shown in solid lines in FIG. 5, and the resilience of the rod will maintain these twisted ends snugly lodged within their respective collar folds.

Thereafter, the other bowed connecting rods are similarly assembled with the collars so that in the assembly both the rods and collars will be held iirmly in their indicated positions. In addition to the intermediate bows, each of the connecting rods or bars has portions 23 and 24 just inside the offset end portions 18 and 19 which extend along and bear against the outer face of the associated collar so as to resiliently maintain the outward bowing of the rods. Thus, in operation in a well bore, as illustrated in FIG. 1, the connecting rods will be firmly lodged in the positions as shown.

Thus, the connector bars or rods for many different sizes of collars may be identical, only the diameters of the end collars being varied. This facilitates the problern of stocking for different requirements. Also, the cost of the centralizer is reduced due to the use of cheaper round stock and simple bending, and the elimination of separate structure for securing the bars in position. The helical disposition of the bars provide a desirable scraping action on the wall of the well bore, for instance, to remove mud cake preparatory to cementing.

Certain modilications may be made in the various parts, as will occur to those skilled in the art and exclusive use of all modications as come within the scope of the appended claims is contemplated.

I claim:

1. A centralizer comprising a pair of spaced collars adapted to be located along a member to be centralized, at least one of said collars having an aperture, and outwardly bowed, resilient elements extending between said amados collars, at least one of said elements being a resiliently flexible -Wire and having an angularly offset end extending through said aperture and torsionally distorted so as to be resiliently lodged against the inner face of said latter collar adjacent 4said aperture to anchor said latter element in position.

2. A centralizer comprising longitudinally spaced collars for embracing a member to be centralized, there be- 3. A centralizer, as described in claim 2 in which said members are disposedy helically between said collars.

4. A centralizer comprising a pair of spaced, axially aligned collars each having a circumferential fold, a series of axially facing recesses in and spaced around each of said folds, and a plurality of outwardly bowed, torsionally resilient wire rods connecting said collars,

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l each rod having a radially offset ends inserted in pairs of said recesses and torsionally twister in the assembly for causing said ends to bear against their receiving folds for anchoring the rod to said collar.

5. A centralizer as described in claim 4 in which each of said rods engages said collars at points inwardly of the rod ends for anchoring said rods in their bowed conditions.

6. A centralizer as described in claim 5 in which the offset ends of each connecting rod extend oppositely whereby said ends anchor said rods against twisting.

7. A centralizeras describedin claim 6 in which said rods are disposed helically with lrespect to said collars.

References Cited in the le of this patent UNITED STATES PATENTS `1,677,050 Reed et al. July 10, 1928 A1,901,518 Johnson Mar. 14, 1933 2,220,237 Hall Nov. 5, 1940 2,717,650 Hall Sept. 13, 1955 2,386,111 Han May 12, 1959 

1. A CENTRALIZER COMPRISING A PAIR OF SPACED COLLARS ADAPTED TO BE LOCATED ALONG A MEMBER TO BE CENTRALIZED, AT LEAST ONE OF SAID COLLARS HAVING AN APERTURE, AND OUTWARDLY BOWED, RESILIENT ELEMENTS EXTENDING BETWEEN SAID COLLARS, AT LEAST ONE OF SAID ELEMENTS BEING A RESILIENTLY FLEXIBLE WIRE AND HAVING AN ANGULARLY OFFSET END EXTENDING THROUGH SAID APERTURE AND TORSIONALLY DISTORTED SO AS TO BE RESILIENTLY LODGED AGAINST THE INNER FACE OF SAID LATTER COLLAR ADJACENT SAID APERTURE TO ANCHOR SAID LATTER ELEMENT IN POSITION. 